50hp EFI Four Stroke Beep Alarm

Fishing4fun

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Joined
Apr 19, 2008
Messages
5
I recently got caught in a bad wind storm that created extreme waves on the lake and when I came close to the shore to let my partner out to go get the trailer backed in to laod up, the waves pushed my boat side ways and up against the bank. This put the motor in shallow water and caused the impeller to suck in a bucket full of sand. I knew then that the water pump was ruined so I shut the motor off. I won't even bother you with the details of how we had to load the boat onto the trailer. Anyway, once back at home, I hooked up the water to the motor via the normal rubber caps coming from the hose. No water from the pee hole. Shut it off, ordered the water pump and changed it out. Also went ahead and changed the motor oil and the gear box oil. Everything went together perfect. Hooked the hose with rubber clamps back up and it peed perfect. It did spit out a little bit of sand at first but then the water was perfectly clear. Also hooked the hose to the pee hole (per the Mercury Manual) and flushed the motor out backwards. Still good clear water coming out. Once going back to the lake , everything went fine as long as I was at idle speed up to around 2000 rpms. Once I tried to go WOT an alarm sounded and the motor started bogging. Went back to just putt-putting and everything was fine. Back to WOT and the same thing happens. The alarm is a constant beep every other second. The only way I can stop the beep is to go to nuetral and turn the key off. Crank back up and everything is fine until I try to go to WOT again. No certain number of beeps, just a beep...beep...beep...beep.... no stop until I turn the key off. The Mercury Manual isn't totally clear on this although it does give some ideas. Any help for a more specific problem? I really can't afford to do a trial and error diagnosis. Thanks to all those who can help. BTW it is a 2006 50hp EFI Four Stroke.
 

Fishing4fun

Recruit
Joined
Apr 19, 2008
Messages
5
Re: 50hp EFI Four Stroke Beep Alarm

After much research and reading the manual about 50 times, I decided to take a chance with the trial and error. I got lucky the first time around. I pulled the thermostat and it had some very tiny pieces of grit caught in it causes it to be stuck open. After cleaning it and placing it back in, I went back to the water to test it. WOT is not a problem and I have no alarms. I am posting this just in case anyone else has the same problem and maybe I can save them the headaches I had to go through.
 
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